bpu: optimize the clock gate efficiency of bpu/predictors_update_* and bpu/previous_*

[Lawrence-ID]

No description provided.

[XiangShanRobot]

[Generated by IPC robot]
commit: 5852d97

commit	astar	copy_and_run	coremark	gcc	gromacs	lbm	linux	mcf	microbench	milc	namd	povray	wrf	xalancbmk
5852d97	1.760	0.458	1.991	1.154	2.930	2.497	2.293	0.928	1.377	1.367	3.167	2.507	2.389	2.852

master branch:

commit	astar	copy_and_run	coremark	gcc	gromacs	lbm	linux	mcf	microbench	milc	namd	povray	wrf	xalancbmk
d73f370
e3da8ba	1.760	0.458	1.991	1.154	2.930	2.497	2.293	0.928	1.377	1.367	3.167	2.507	2.389	2.852
1b353ff	1.768	0.458	1.991	1.154	2.930	2.497	2.293	0.928	1.377	1.367	3.167	2.507	2.389	2.852
ad79215	1.760	0.458	1.991	1.154	2.930	2.497	2.293	0.928	1.377	1.367	3.167	2.507	2.389	2.852
7a63335	1.760	0.458	1.991	1.154	2.930	2.497	2.293	0.928	1.377	1.367	3.167	2.507	2.389	2.852
5ca12de	1.760	0.458	1.991	1.154	2.930	2.497	2.293	0.928	1.377	1.367	3.167	2.507	2.389	2.852
bfac330	1.768	0.458	1.991	1.154	2.930	2.497	2.293	0.928	1.377	1.367	3.167	2.507	2.389	2.852
70eea12	1.768	0.458	1.991	1.154	2.930	2.497	2.293	0.928	1.377	1.367	3.167	2.507	2.389	2.852
f835884	1.760	0.458	1.991	1.154	2.930	2.497	2.292	0.928	1.377	1.367	3.167	2.507	2.389	2.852
9718f93	1.760	0.458	1.991	1.154	2.930	2.497	2.293	0.928	1.377	1.367	3.167	2.507	2.389	2.852

[eastonman]

splited into #3541 #3670